The invention relates to the method and apparatus or system for producing a perspective three dimensional type carving of various sizes in an object utilizing an interrelated set of tools or dies. The products obtained by the present invention exhibit a unique visual effect which may be used on a variety of shaped objects.
The present invention refers to ultrasonic abrasive slurry machining, also known as ultrasonic impact grinding. Ultrasonic slurry machining has been disclosed in U.S. Pat. No. 2,580,716 issued to L. Balamuth dated Jan. 1, 1952, entitled "Method and Means for Removing Material from a Solid Body" and is described also in Ultrasonic Engineering (book) by Julian R. Frederick, John Wiley & Sons, Inc., New York, NY (1966) pages 171 to 183.
The ultrasonic abrasive slurry machining process involves the use of an ultrasonically vibrating tool which is in contact with or slightly spaced from a workpiece. Abrasive particles suspended in a fluid are fed into the gap between the tool and the object or workpiece and are driven with a percussive impact against the workpiece. The high velocity impact of the particles on the workpiece causes an abrading action which is used for producing accurate odd-shaped holds and recesses in hard materials, such as carbides, ceramics, glass, and semi-conductors.
The above process has been used for the carving of glass or crystal to obtain a variety of objects on plates, blocks, ash trays, paper weights, etc. One of the limitations of the above process relates to the diameter of the carving which has been handicapped by the practical limitations of existing vibration transmitting members. The limitations are in the planes perpendicular to the direction of the vibrations to be transmitted. The technical reasons for this are fully explained in U.S. Pat. No. 3,113,225 to Kleesattel et al., of which the present applicant is a co-inventor. With increases in the effective or working dimension of the vibration transmitting member beyond a certain value, the costs of producing a transducer increase disproportionately to become prohibitive.
Although the above Kleesattel et al. patent is applicable to both longitudinal and circular configurations, there are limitations for circular vibration transmitting members. At 20 KHz a tool in excess of approximately 3 inches in diameter presents carving problems as to the flow of abrasive slurry between the tool output surface and the object. Towards this end applicant has found that not withstanding the Klessattel et al. teachings a larger circular tool produced in accordance therewith still presents ultrasonic carving problems. In addition, the power to vibrate a tool of approximately 5-6 inches in diameter exceeds that of generally available conventional instruments.
The prior carving systems due to the inherent limitations of the diameter of the tool as explained above initially led the inventor to attempt to separate a single totality into say two or more carving tools since a single tool could not carve the design in one movement. Upon separating of the carving into individual sections and then carving each one adjacent the other, the inventor found that for most carvings horizontal registration of the tools became a time exacting task that could not be jigged. When the registration on a horizontal plane was not obtained a dividing line was visible in the end product that was not acceptable for commercial sale. Accordingly, the carving of a 5 inch diameter carving with a 20 KHz motor was not practicable with the prior art teachings even if carved in adjacent sections. Applicant found that variations in mounting of the replaceable tools to be ultrasonically vibrated could not be reproduced with an exactness to avoid a visible spacing between the carved sections.